This led to a debate, not just amongst bored commuters on the Piccadilly line, but also amongst Internet users at home with even more valueless time on their hands, over what the correct punctuation should be. Most people agreed that commas sequence related items, and so something else should be used to separate things you should and shouldn't do, assuming:

-(a, b, c, d) ≠ -(a) + (b, c, d)

Usingenglish.com ran a poll and 62% of respondents said the first comma should be replaced with a full stop. 19% would have used an em dash, 14% a semi-colon and 5%
were happy with the comma.